Dataspace Use Case #4 - netCDF with Unlimited Dimensions

User would like to create a two 3-D datasets with the same dimensions used for each dataset's dataspace. Additionally, one of the shared dimensions is "unlimited" and each dataset's dataspace needs to reflect the maximum of the allocated size for that dimension as it's current size.

Route:

1. User creates a dimension to be used for dimension #0 in dataspace.
2. User "commits" dimension to file, giving it a name. ("X")
3. User creates a dimension to be used for dimension #1 in dataspace.
4. User "commits" dimension to file, giving it a name. ("Y")
5. User creates a dimension to be used for dimension #2 in dataspace.
6. User "commits" dimension to file, giving it a name. ("Z")
7. User creates a 3-D dataspace with dimension objects.
8. User creates a dataset 'A' with 3-D dataspace.
9. User creates a dataset 'B' with 3-D dataspace.
10. User extends dimension #2 ("Z") in dataset 'A'.
11. User queries dataset 'B's current dimension sizes and should get sizes that reflect dimension #2 ("Z") being extended in dataset 'A'.